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Monthly Archives for February 2008

Robert Rapier, over at the R-Squared Energy Blog, has posted an interesting quick look at using ocean currents as a source of energy. This is, of course, another way of capturing part of the planet’s total solar energy budget as well as some of the energy from the tides as well. Interesting read.

In regards to my previous post on the recent studies on biofuels, WorldChanging has posted an article about the issue, citing a study released by the Sierra Club as well as the Science report. The WorldChanging blog post mentions that the Science report “reinforced the urgency of moving to second-generation biofuels.”

In considering this topic, I think something else extremely valuable is coming out of the biofuel boom. We’re learning how to quickly estimate environmental costs.

I posted a quick note earlier about installing porous asphalt in a green community in Oregon. In that note, I made an offhand comment questioning the water quality coming off the road. After posting the article, I also wondered if the lifetime of the surface would be shorter in areas prone to freezing weather due to the expansion and contraction of ice in the pores.

It turns out that had I been less lazy in doing my research, I’dve had all these questions answered much more quickly. I just found a great article on porous asphalt that covers a lot of topics, including water quality (82% removal efficiency for organic carbon) and lifetime in freezing weather (longer than standard asphalt).

Additionally, the article points out that the porosity allows for less use of salts for deicing and that:

The water drains through the pavement and into the bed below with sufficient void space to prevent any heaving or damage, and the formation of “black ice” is rarely observed. The porous surfaces tend to provide better traction for both pedestrians and vehicles than does conventional pavement. Not a single system has suffered freezing problems.

Pretty darned cool, if you ask me. One has to ask what the factors are that are keeping this from being installed in every new parking lot being built. Undoubtedly, the subsurface strata affect the design – this is also covered in the article – but I suspect strong that the major factor is simply ignorance.

On a lighter note, the best quote from the article is this one: “Fortunately, even without regular maintenance, the systems continue to function (we routinely send graduate students and recent hires out in hurricanes to confirm this).”

In the alternative energy circles, a recent Science magazine online article published by a group from Minnesota has been making a lot of waves in the media. This article from the Seattle Times is typical of the coverage. There are a couple of issues with both the article and the coverage of the article that I’d to point out.

First, let me tackle the article. While no one will argue that corn ethanol is an extremely poor choice for a biofuel feedstock, it is also inarguable that the article focused on current biofuel technology. This implicitly assumes that all new biofuels will be roughly equally bad for the environment. Clearly, this is not the case, since algal-derived biodiesel and similar biomass-derived fuels will not contribute equally to global warming through the destruction of ecosystems. The article also assumed by implication that biofuels are the primary driver behind conversion of ecosystems to cropland. Past data would indicate that this is almost certainly not the case, since slash-and-burn was prevalent in the Amazon basin well before biofuels become a cause celebre. The issues around land use in the developing world would exist with or without biofuels contributing, since there is rarely an incentive for the governments who control these lands to preserve them. Rain forests do not yield significant economic benefit to those who live near them. All the biofuel boom has done is exacerbate the situation. Hopefully, this will bring attention to dealing with the root causes of the destruction of these ecosystems – namely, food security and poverty.

The media has been largely guilty of indulging in shrill hachet jobs on the nascent biofuel industry based on this article. I am certainly not implying that the authors of the Science report intended this; rather, I think that the natural tendency to want to take potshots at large targets is to blame here. Nevertheless, I think its important that people interested in short term energy development continue to work on capturing energy from biomass. With any luck, we’ll solve both the petroleum problem and the disappearing ecosystems problem at the same time.

I’m in Chicago this week on business. Things started off with a cancelled flight for both me and one of my teammates (two separate flights). Then, our first trial completely bombed, forcing me to revise the experimental plan somewhat. And to top it off, the 4th guy on the team who was coming had 3 flights cancelled or delayed, making him 24 hours late. Go Chicago-O’hare!

We’re up and going now and I’m sitting in the lab working on a new model for the data we’re collecting while I watch the equipment run.

After reading this post from WorldChanging, I wondered a bit about the wisdom of porous pavement. Sure, I understand the issues that are caused by stormwater runoff, but I’m a little concerned about what gets washed off the streets through the pores in the pavement.

There are probably good ways to handle this, including beds of Stropharia mushrooms on either side of the road to mycoremediate the waste water stream or even a filter layer underneath the pavement.

I also wonder what is actually underneath that pavement. Is it the sand and gravel bed that typically underlies roadways? Or is it something else more porous? The percolation through a layered gravel bed might reduce the pollution in the water that passes through.